Volcanic Hazards on the Island of Hawai`i

Lava flows are the primary hazard

Lava entering sea can be dangerous

Ever since lava first erupted above sea level over 500,000
years ago to begin building the Island of Hawai`i, countless
eruptions from its five volcanoes have built the "Big Island"
to a towering height of more than 4,000 m (13,000 ft). Its
two most active volcanoes -- Mauna Loa and Kilauea -- erupt
lava frequently enough to pose a serious hazard to property
on many parts of the island. About 40 percent of Mauna Loa
has been covered by lava in the past 1,000 years and over
90 percent of Kilauea's surface is covered by lava less
than 1,100 years old. As land development expands toward
areas of relatively high hazard, the threat to life and
property on Hawai`i will increase accordingly.

When lava meets the sea

New land the size of several football fields can collapse
into the ocean with little or no warning, and the intensity
of lava-seawater explosions can change suddenly. Find out how
new land is created when lava enters the sea and how to
identify areas near lava-entry points that are safe for viewing.

Hazard zones from lava flows are based chiefly on the location and
frequency of historic and prehistoric eruptions and the topography
of the volcanoes. Scientists have prepared a map that divides the five
volcanoes of the Island of Hawai`i into zones that are ranked from 1
through 9 based on the relative likelihood of coverage by lava flows.